Distribution authorized for Public Release: March, 2011.
NDIA – 46th Annual Gun & Missile Systems Conference & Exhibition
August 2011
Novel ARDEC
Igniters for Gun
Systems
Dr. Eugene Rozumov, D. Park, T. Manning, C.P. Adam, J. O’Reilly, J. Laquidara,
E. Caravaca
Armament Research Development Engineering Center
Distribution authorized for Public Release: March, 2011.
Distribution authorized for Public Release: March, 2011.
STAR ATO
High Performance Igniter
Problems: Benite doesn’t perform as well as BKNO3 in
120MM tank rounds
Benite gives inconsistent performance results.
Future rounds need smaller igniter tubes.
Solution: ARDEC has developed an igniter formulation
• Excellent and consistent performance
• Less sensitive than Benite
• Is more energetic than Benite.
• Extrudable
• Smaller Ignition Delays
Distribution authorized for Public Release: March, 2011.
Possible Causes:
Type IV BKNO3 igniter has
an oxygen balance of -35%
• After firing, all of the oxygen
in the barrel is exhausted
• Boron combustion requires
large amounts of oxidizer
• Opening of breach allows a
rapid influx of oxygen which
ignites uncombusted boron
(or other fuel)
High Performance Igniter
BKNO3
Made of: 70% Potassium Nitrate
30% Boron
Easily ignited at low P.
High Gas Content
Burn Rate insensitive to P.
Hygroscopic (less than Black Powder)
Flare Back (Incomplete oxidation)
Benite
Made of: 40% Nitrocellulose
6.3% Sulfur
44.3% Potassium Nitrate
9.3% Charcoal
0.5% Ethyl Centralite
Performance as an igniter is adequate for tank applications.
Distribution authorized for Public Release: March, 2011.
Properties of Binders
Considered
O
N3
N3
O
N3
N3
O
N3
N3
O
O
N3
O
N3
O
N3
O
O
ONO2
O O
O2NO ONO2O
ONO2
ONO2
O2NOO
O
OR
O O
RO ORO
OR
ORROO
R =
O O
Nitrocellulose
ρ = 1.66 g/cc
ΔHf = -690 kJ/mol
Tv = 3331 K
O.B. = -31%
Cellulose Acetate/Butyrate
ρ = 1.22 g/cc
ΔHf = -1630 kJ/mol
Tv = 1052 K
O.B. = -160%
Glycidyl Azide Polymer (GAP)
ρ = 1.29 g/cc
ΔHf = 176 kJ/mol
Tv = 2288 K
O.B. = -121%
poly-Bis-AzidoMethyl-Oxetane
ρ = 1.30 g/cc
ΔHf = 373 kJ/mol
Tv = 2246 K
O.B. = -124%
Distribution authorized for Public Release: March, 2011.
-100.0
-50.0
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
0.000 2.000 4.000 6.000 8.000 10.000
Pre
ssu
re (M
Pa)
Time
Pressure 1 (MPa)
Pressure 2 (MPa)
Pdiff (MPa)
FNGUN Analysis
Instantaneous
Ignition along the
igniter tube.
No Pressure
Differentials. 0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
1400.0
1600.0
1800.0
0 1 2 3 4 5 6
Pre
ssu
re (M
pa)
Time
Pressure base
Pressure tip
Pdiff
Staged Ignition from the
middle of the igniter
tube.
-50 MPa Pressure
Differentials.
Distribution authorized for Public Release: March, 2011.
Sensitivity Analysis
Lot # Diameter Result
8551 0.1345 NOGO
8551 0.1350 NOGO
8558 0.1405 NOGO
8558 0.1415 NOGO
8556 0.1420 NOGO
8556 0.1440 NOGO
8557-3 0.1400 NOGO
8557-3 0.1385 NOGO
Material Burn Time Explosion Detonation Pass/ Fail
PAI-8556
Less 1 Sec. NO NO Pass
Less 1 Sec. NO NO Pass
Less 1 Sec. NO NO Pass
PAI-8557
Less 1 Sec. NO NO Pass
Less 1 Sec. NO NO Pass
Less 1 Sec. NO NO Pass
PAI-8558
2.01 Sec. NO NO Pass
2.79 Sec. NO NO Pass
3.05 Sec. NO NO Pass
Material Starting Weight Total Loss Pass - Fail
PAI 8556 50.4135gms .1464gms PASS
PAI 8557 50.2485gms .2614gms PASS
PAI 8558 50.2745gms .1545gms PASS
Critical Diameter
Thermal Stability
Small Scale Burn
Formulation
Igniter Sensitivity
Impac
t ERL
(cm)
BOE
Friction
(GO / No
GO) (N)
ESD
(J)
Benite 18.8 6 of 10 288 / 252 >0.25
BKNO3 23.2 10 of 10 > 360 >0.25
PAI-8556 22.4 7 of 10 240 / 216 >0.25
PAI-8557 24.6 5 of 10 324 / 288 >0.25
PAI-8558 >100 0 of 10 252 / 240 >0.25
Distribution authorized for Public Release: March, 2011.
Small Scale Ignitability Study
Distribution authorized for Public Release: March, 2011.
Expected Data
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Benite at Ambient
Temperature
Ambient Temperature.
5 shots
P never returned to zero
No Negative Pressure
Differentials
Distribution authorized for Public Release: March, 2011.
PAI-8557 Un-Ground BKNO3
Distribution authorized for Public Release: March, 2011.
Analysis of Pmax and t2
0
0.5
1
1.5
2
2.5
3
Pmax (kpsi) ΔPmax (kpsi) t2 (msec) Δt2 (msec)
Benite 21C S1
PAI-8556-2 S1
PAI-8556-6 S1
PAI-8557 S1
Benite 21C S2
PAI-8556-2 S2
PAI-8556-6 S2
PAI-8557 S2
Pmax ΔPmax τ2 Δτ2
Distribution authorized for Public Release: March, 2011.
Analysis of t5 and t6
0
0.5
1
1.5
2
2.5
3
3.5
4
t5 (msec) Δt5 (msec) t6 (msec) Δt6 (msec)
Benite 21C S1
PAI-8556-2 S1
PAI-8556-6 S1
PAI-8557 S1
Benite 21C S2
PAI-8556-2 S2
PAI-8556-6 S2
PAI-8557 S2
τ5 Δτ5 τ6 Δτ6
Distribution authorized for Public Release: March, 2011.
0
1
2
3
4
5
6
th1 (msec) Δth1 (msec) th2 (msec) Δth2 (msec) th (msec) Δth (msec)
Benite 21C S1
PAI-8556-2 S1
PAI-8556-6 S1
PAI-8557 S1
Benite 21C S2
PAI-8556-2 S2
PAI-8556-6 S2
PAI-8557 S2
τh1 Δτh1 τh2 Δτh2 τh Δτh
Analysis of th1, th2, and th
Distribution authorized for Public Release: March, 2011.
High Speed Video Stills of Benite
Igniter at Ambient Temperature
Distribution authorized for Public Release: March, 2011.
High Speed Video Stills of PAI-8556 at
Ambient Temperature
Distribution authorized for Public Release: March, 2011.
High Speed Video Stills of PAI-8556 at
Ambient Temperature
Distribution authorized for Public Release: March, 2011.
Conclusions
Benite was found to have significant shot to shot
variability in terms of pressure and time.
Extrudable BKNO3 analogue igniters were able to
achieve Pmax faster than benite with less variance
in ignition delays and output pressures than
benite demonstrating that the analogue igniters
are more consistent.
High speed video of the ignition events also
demonstrated more hot particle and flame
generation in the BKNO3 analogue igniters in
comparison to benite.